Ice Sheet Disintegration

Ice sheet change is expected to be a "slow" climate feedback. How rapidly ice sheets can
disintegrate is one of the most uncertain and imporant climate issues. The dominant physical
process causing ice sheet disintegration may be absorption of heat by the ocean (due to an
increasing greenhouse effect), resulting melting of ice shelves, and thus an increased rate of
discharge of ice from the ice sheet to the ocean. Once this process gets well underway, it may be difficult to
prevent accelerating ice sheet disintegration under its own impetus (
http://pubs.iss.nasa.gov/docs/2005/2005_Hansen.pdf).

Also in PDF. (last modified 2012/12/25)

Also in PDF. (last modified 2012/12/27)

Also in PDF. (last modified 2013/01/17)

The figures above show the rate of mass loss from the Greenland and Antarctic ice sheets, based on a recent publication by Shepherd et al. (2012).
The rate of mass loss from Greenland has increased
during the past several years, as it has from Antarctica. This is one of the most important
geophysical measurements being made, so it is important to get a follow-on gravity satellite into
space. A planned European gravity satellite is not sufficiently capable to yield accurate ice sheet
mass change, and a planned NASA follow-on gravity mission is low on NASA's priority list.

We thank Dr. Eric Rignot for providing us digital data of an earlier version of "input output method" data, and Drs. Andrew Shepherd and Erik Ivins for providing the digital Antarctica mass data of their paper. All other data were read off from Fig. 4 of their paper.